Sewing machine cam selector mechanisms



D. P. BUAN ETAL 3,503,350

SEWING MACHINE CAM SELECTOR MECHANISMS March 31, 1970 2 Sheets-Sheet 1' Filed Nov. 20, 1967 IAIJ VENTORS Dani/o Buan And August Monteiro Witness March 31', 1970 'D! BUAN ETAL 3,503,350

SEWING MACHINE CAM SELECTOR MECHANISMS Filed Nov. 20, 1967 2 Sheets-Sheet 2 INVENTORS Dam/o P. Buan And August Monfeiro Witness BY United States Patent 3,503,350 SEWING MACHINE CAM SELECTOR MECHANISMS Danilo P. Buan, Old Bridge, and August Monteiro, Kearny, N.J., assignors to The Singer Company, New York, N.Y., a corporation of New Jersey Filed Nov. 20, 1967, Ser. No. 684,425 Int. Cl. D05b 3/02 U.S. Cl. 112-158 7 Claims ABSTRACT OF THE DISCLOSURE A cam selector mechanism is disclosed for a multi-cam zigzag sewing machine in which the spring bias exerted by the needle jogging control linkage on the cam follower is withdrawn from the cam follower during ca-m selection by operation of the same cam selecting mechanism by Which the cam follower is shifted from one. cam to another so that the cam follower is substantially free of frictional drag while being moved from one cam to another.

BACKGROUND OF THE INVENTION This invention relates to zigzag sewing machines having a plurality of individually selectable pattern cams for producing predetermined patterns of zigzag stitches, and more particularly, to operator influenced mechanisms for effecting selection of the pattern cam which will be utilized to influence the zigzag stitching.

DESCRIPTION OF THE PRIOR ART It is well known in the art to provide a zigzag sewing machine with a plurality of pattern cams each with differently contoured edges but all arranged in a stack, and with a cam follower located between a needle jogging control linkage and the cam stack and shiftable relatively to the cam stack into tracking relation with the edge of any selected one of the pattern cams. In these known zigzag machines the needle jogging control linkage is commonly biased against the cam follower and it is the bias of the needle jogging control linkage which urges the cam follower into tracking relation against the selected pattern cam edge. When it is desired to change the zigzag stitch pattern of such known sewing machines, the cam follower must be moved sufficiently far from the cam stack so that it can clear the pattern cam edges during the relative shifting movement and in so doing, the bias exerted by the needle jogging control linkage must be overcome.

In the United States Patent to Johnson No. 2,862,468, Dec. 2, 1958 the bias of the needle jogging control linkage is continuously applied to the cam follower when the cam follower is forced away from the cam stack and while the cam follower is shifted relatively to the cam stack. A relatively high frictional drag is imposed upon the shifting movement of the cam follower during cam selection, thus making selection difficult.

In the United States Patent to March et al. No. 3,191,559, June 29, 1965 spring release mechanism is provided for removing the bias of the needle jogging control linkage during cam selection. In this patented construction auxiliary cam means are required for re-engaging the biasing spring of the needle jogging control linkage after cam selection, and the resulting biasing spring control mechanism is quite complex and expensive.

SUMMARY OF THE INVENTION It is a primary object of this invention to provide a cam selector mechanism for a zigzag sewing machine having a cam stack, a cam follower shiftable into tracking relation with any selected one of a plurality of cams in the cam stack, and a spring biased needle jogging linkage engaging and urging the cam follower against the cam stack, in which during cam selection the spring bias of the needle jogging linkage is withdrawn from the cam follower by the operation of a manually influenced member separate from the cam follower thus freeing the cam follower for shifting movement substantially free of frictional drag.

Another object of this invention is to provide an improved cam selector mechanism in accordance with the foregoing object in which the spring bias of the needle jogging linkage is withdrawn from the cam follower during cam selection by manual operation of the same cam selecting mechanism by which the cam follower is shifted from cooperation with one cam to another.

DESCRIPTION OF THE DRAWINGS Other objects and a fuller understanding of the invention can be had by referring to the description and claims taken in conjunction with the accompanying drawings in which:

FIG. 1 is a top plan view of a sewing machine with the top cover removed to show the improved cam selector mechanisms;

FIG. 2 is a perspective view of the cam selector mechanism for the forward cam follower with the handle of the cam selector mechanism for the rear cam follower shown in phantom; and

FIG. 3 is a perspective view of the cam selector mechanism for the rear cam follower with the handle of the cam selector mechanism for the forward cam follower shown in phantom.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the drawings, in FIG. 1 the invention is shown embodied in a sewing machine having a frame 11 of which the top of a standard 12, a bracket arm 13 extending laterally from the top of the standard, and a sewing head 14 at the free end of the bracket arm are shown. The top cover is removed to show the inside of the bracket arm. A control panel 15 is connected to the front of the bracket arm and standard.

Mounted in the sewing head is a needle bar gate 20. The needle bar gate is pivotally connected at an intermediate portion to the sewing head by a hinge pin 21. A needle bar 22 is slidably mounted in the front end of the needle bar gate. Endwise reciprocating motion is imparted to the needle bar by a conventional crank mechanism indicated generally at 23. The crank mechanism is mounted on the head end of an arm shaft 24 which extends longitudinally through the bracket arm and is journaled in two partitions 25 and 26, one in the head end of the bracket arm and the other in the top of the standard. A handwheel 27 is mounted on the standard end of the arm shaft. Pivotally connected to the rearmost end of the needle bar gate by a pivot screw 28 is a connecting rod 29, the free end of which extends into the bracket arm. An integrating plate 30 is pivotally connected to the free end of the connecting rod by a vertical hinge pin 31. Pivotally mounted in the bottom of the bracket arm in the vicinity of the integrating plate by a pivot pin 32 is a bell crank 33 having two arms 34 and 35. One of the arms of the bell crank is formed in the shape of a hook. A main tension coil spring 36 is stretched between the hooked arm 34 of the bell crank and a stud 37 in the sewing head biasing the other arm of the bell crank against the integrating plate States Patent of R. E. Johnson, No. 2,862,468, granted Dec. 2, 1958. The cam stack includes a vertical cam shaft 39 which is journaled in the bottom of the bracket arm. Rotation is imparted to the cam shaft through a worm 40 on the arm shaft and a mating worm wheel 41 on the cam shaft. A plurality of cams 42 having peripheral cam surfaces 43 are mounted on the cam shaft and are fixed to rotate with the cam shaft by a vertical pin 44.

Mounted in the bracket arm beside the cam stack are two cam follower mechanisms indicated generally at 45 and 46. The cam follower mechanisms are mounted on two posts 47 and 48 which are carried vertically in the bottom of the bracket arm parallel to the cam shaft.

In FIG. 2, the front cam follower mechanism 45 is illustrated with the parts associated therewith. As shown in FIG. 2, a bell crank 49 is mounted on the forward post. The bell crank includes a collar 50 by which it is slidably mounted on the post, a free arm 51, and a cam follower arm 52. The cam follower arm extends between the cam stack and the integrating plate 30 and has a cam following projection 53 which tracks the peripheral cam surface 43 of one of the, cams, as well as a contacting surface 54 which contacts the integrating plate. Slots 55 corresponding to vertical spacing of the cams are formed in the post 47, and a slot 56 is formed in the collar to communicate with a selected one of the slots in the post. A blade 57 extending perpendicularly from a bracket 58 slidably seats in the slot in the collar and in a selected one of the slots in the post. The bracket is pivotally connected by a pivot screw 59 to a crank arm 60. The crank arm is perpendicularly connected to oneof two arms 61 and 62 of a U-shaped bracket 63 which is pivotally mounted on a rod 64 with the rod spanning the two arms of the bracket. The rod is slidably journaled in two bosses 65 and 66 in the bracket arm. A hollow sleeve 67 is pivotally mounted on the rod with one end connected to the innermost arm 62 of the U-shaped bracket 63. A bearing flange 68 is formed on the free end of the hollow sleeve. A crank arm 69 is formed on the free end of the outermost arm 61 of the U-shaped bracket 63 and extends through the front of the bracket arm and the control panel. A knob 70 is pressed onto the free end of the last mentioned crank arm 69. The cam follower arm 52 of the bell crank is biased away from the peripheral cam surface 43 of one of the cams and towards the integrating plate 30 by a torsion spring 71 mounted by a screw 72, on the bracket 58. A limb 73 of the torsion spring bears against the free arm 51 of the bell crank 49.

In FIG. 3, the rear cam follower mechanism 46 is illustrated together with the parts associated therewith. As shown in FIG. 3, a bell crank 74 is slidably pivoted on the rear post 48. As in the case of the bell crank 49 on the forward post, the bell crank 74 includes a collar 75 by which it is slidably mounted on the post, a free arm 76, and a cam follower arm 77. The cam follower arm extends between the cam stack and the integrating plate 30 and has a cam follower 78 which tracks the peripheral cam surface 43 of one of the cams and a contacting surface 79 which contacts the integrating plate. Slots 80 corresponding to the vertical spacing of the cams are formed in the post 48 and a slot 81 is formed in the collar 75 to communicate with a selected one of the slots in the post. Again, as in the case of the bell crank 49 on the forward post, a blade 82 extending perpendicularly from a bracket 83 slidably seats in the slot 81 in the collar and in one of the slots 80 in the post. The bracket 83 is pivotally connected by a pivot screw 84 to a crank arm 85 which is fast on a collar 86 by which the crank arm 85 is secured on the end of the rod 64 by a set screw 87. Also mounted on the rod 64 by a set screw 88 is a bracket 89 which is mounted between the arms of the U-shaped bracket 63. A crank arm 90 is formed on the bracket 89 and extends through the front of the bracket arm and the control panel. A knob 91 is pressed onto the free end of the last mentioned crank arm 90.

In order to move the integrating plate 30 out of contact with the cam follower arm 52 on the forward post when the cam follower is being moved from one cam to another, a bell crank throw-out lever 92 is pivotally mounted on the rear post, as shown in FIG. 2. The lever 92 has a free arm and a contacting arm 94 which extends between the cam stack and the integrating plate for contacting the integrating plate. A bracket 95 is mounted on the free arm 93 of the throw-out lever by two screws 96. The bracket 95 has an upwardly extending bearing arm 97 which contacts the end of the bearing flange 68 on the sleeve 67 and an arm 98 having a notch "99. The bearing flange 68 on the sleeve 67 thus constitutes projection means on the operator influenced assembly 63, 67, 70 by which the throw-out lever can be operated. A tension coil spring 100 is stretched between the notch 99 and a second notch 101 in an arm 102 on a second bracket 103 mounted in the bracket arm by two screws 104. The tension coil spring 100 biases the contacting arm 94 of the bell crank lever away from the integrating plate 30 and biases the upwardly extending bearing arm 97 against the end of the bearing flange 68 on the sleeve.

In order to move the integrating plate 30 out of contact with the cam follower arm 77 on the rear post 48 when the cam follower is being moved from one cam to another, a second bell crank throw-out lever 105 is pivotally mounted on the rear post, as shown in FIG. 3. The second throw-out lever is held on the post by a split ring clip 106 and has a U-shaped free arm 107 having two limbs 108 and 109 and a cross-bar 110- between the limbs. The rear post 48 spans the two limbs with the cross-bar oriented vertically and parallel to the post. The second throw-out lever 105 also has a contacting arm 111 which extends between the cam stack and the integrating plate 30 for contacting the integrating plate. The crank arm 85 on the end of the rod 64 constitutes a projection means on the operator influenced rod 64 by which the throw-out lever 105 can be operated by contacting the forward edge of the cross-bar 110 of the U-shaped free arm of the second throw-out lever. The free arm 76 of the bell crank cam follower 74 on the rear post contacts the rear edge of the cross-bar 110 to hold the contacting arm 111 of the throw-out lever 105 out of contact with the integrating plate 30 except while cam selection is being accomplished.

In operation, with particular reference to FIG. 2, when it is desired to move the cam follower 53 on the forward post from one cam to another, an operator pushes against the knob 70 on the crank arm which extends through the front of the bracket arm and the control panel. The foregoing movement shifts the U-shaped bracket 63 and sleeve 67 axially on the rod 64 to cause the bearing flange 68 on the end of the rod to push the upwardly extending bearing arm 97 against the pull of the tension coil spring 100. The foregoing movement causes the throw-out lever 92 to pivot, with the contacting arm 94 of the throw-out lever pushing the integrating plate 30 against the force of the main tension coil spring 36 out of contact with the contacting surface 54 of the cam follower arm 52. The shifting movement of the U-shaped bracket 63 on the rod 64 also pushes the perpendicularly extending blade 57 out of the slot 55 in the forward post so that the bell crank cam follower 49 is free to move axially on the post. The perpendicularly extending blade, although out of contact with the post, remains in the edge of the slot 56 in the collar 50. Clockwise cranking movement of the crank arm 69 causes the bell crank cam follower 49 to move downwardly on the post while counterclockwise cranking movecam follower arm 52 can be moved to a position opposite another cam without contacting the integrating plate. When the cam follower arm is opposite the desired cam, the crank arm 69 is released causing the perpendicularly extending blade 57 to seat in the appropriate slot 55 in the post to lock the bell crank arm follower 49 against axial movement on the post. Simultaneously, the contacting arm 94 of the throw-out lever 92 is allowed to be pulled away from the integrating plate 30 by the tension coil spring 100, and the main tension coil spring 36 biases the integrating plate against the contacting surface 54 of the cam follower arm 52.

With particular reference to FIG. 3, when it is desired to move the cam follower 78 on the rear post from one cam to another, the operator pushes against the knob 91 on the crank arm 90 which extends through the front of the bracket arm and the control panel. The foregoing movement shifts the rod 64 and the crank arm 85 on the end of the sleeve to push the cross bar 110 of the U- shaped free arm 107 of the second throw-out lever 105 against the force of the main tension coil spring 36 exerted through the free arm 76 of the bell crank cam follower 74 on the rear post. The foregoing movement causes the throw-out lever 105 to pivot, with the contacting arm 111 of the throw-out lever pushing the integrating plate 30 against the force of the main tension coil spring 36 out of contact with the contacting surface 79 of the cam follower arm 77. The shifting movement of the crank arm 85 on the end of the rod 64 also pushes the perpendicularly extending blade 82 out of the slot 80 in the rear post so that the bell crank cam follower 74 is free to move axially on the post. The perpendicularly extending blade, although out of contact with the post, remains in the edge of the slot 81 in the collar. As in the case of the bell crank cam follower 49 on the forward post, clockwise cranking movement of the crank arm 90 causes the bell crank cam follower 74 to move downwardly on the post while counterclockwise cranking movement of the crank arm causes the bell crank cam follower to move upwardly on the post. The cam follower 78 is held far enough away from the cam surfaces 43 of the cams 42 by the action of the cross bar 110 of the U-shaped free arm 107 of the second throw-out lever 105 against the free arm 76 of the bell crank cam follower 74 to clear all of the cams, and the integrating plate 30 is held out of contact with the contacting surface 79 of the cam follower arm 77 by the contacting arm 111 of the second throw-out lever 105. Thus, the cam follower arm 77 can be moved to a position opposite another cam without contacting the integrating plate. When the cam follower arm is opposite the desired cam, the crank arm 85 is released causing the perpendicularly extending blade 82 to seat in the appropriate slot 80 in the post to lock the bell crank arm follower 74 against axial movement on the post. Simultaneously, the contacting arm 111 of the second throw-out lever 105 is moved away from the integrating plate 30 by action of the main tension coil spring 36 through the free arm 76 of the bell crank cam follower 74 on the rear post, and the main tension coil spring biases the integrating plate against the contacting surface 79 of the cam follower arm 77.

It is understood the either or both of the cam followers 53 and 78 can be moved to other cams to change the stitch pattern. The invention permits the foregoing movements without hindrance from the integrating plate 30 to sharply reduce wear of parts and without adding any new operations on the part of the operator. The integrating late is moved out of the way of a cam follower arm 52 or 77 during the very same operation by which the cam follower arm is moved to another cam.

Although the invention has been decribed in it preferred from with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made by way of example and that numerous changes in the details of construction and the combination and arrangement of parts can be resorted to without departing from the spirit and the scope of the invention.

Having thus set forth the nature of this invention, what we claim herein is:

1. In combination with a zigzag sewing machine having a needle jogging control linkage, a plurality of pattern cams arranged in a cam stack, a cam follower interposed between said needle jogging control linkage and said pattern cams, means shiftably supporting said cam follower for movement into tracking relation with any selected one of said pattern cams, and spring means biasing said needle jogging control linkage against said cam follower, a cam selector mechanism comprising operator influenced cam follower shifting means carried on said sewing machine for shifting said cam follower into tracking relation with any selected one of said plurality of pattern cams, a bell crank throw-out lever shiftably supported on said sewing machine in spaced relation to said cam follower, said bell crank throw-out lever having an effective position in engagement with said needle jogging control linkage and sustaining said needle jogging control linkage out of said biased position against said cam follower, and a projection carried by said operator influenced cam follower shifting means for engaging a free arm of said bell crank throw-out lever and maintaining said bell crank throw-out lever in effective position during shift of the pattern cam tracking relation of said cam follower.

2. The combination set forth in claim 1 which includes means for biasing the contacting arm of the bell crank throw-out lever away from engagement with said needle jogging control linkage.

3. The combination as set forth in claim 2 in which the cam follower is a bell crank lever having a free arm which contacts the free arm of the bell crank throw-out lever to shift the contacting arm of the bell crank throw-out lever out of engagement with the needle jogging control linkage when the bell crank cam follower is in contact with the cam surface of one of the cams.

4. In combination with a zigzag sewing machine having a plurality of cam followers arranged for tracking relation each with a selected one of said plurality of pattern cams, a needle jogging control linkage including an integrating plate engageable by said plurality of cam followers, and spring means biasing said integrating plate against said plurality of cam followers, a cam selector mechanism comprising separate operator influenced cam follower shifting means carried on said sewing machine, one cooperating with each of said plurality of cam followers for shifting said cam followers into tracking relation with any selected one of said plurality of pattern cams, separate throw-out member shiftably supported on said sewing machine and associated one with each of said plurality of cam followers, said throw-out members each having an effective position in engagement with said integrating plate and sustaining said integrating plate out of said spring biased position against the cam follower associated with said throw-out member, and means carried by each of said separate operator influenced cam shifting means for shifting and maintaining in effective position that one of said throw-out members which is associated with the cam follower shifted by said operator influenced means during shift of the pattern cam tracking relation of said last mentioned cam follower.

5. The combination as set forth in claim 4 in which each of the throw-out members are bell crank levers and each of the operator influenced cam follower shifting means includes a projection means which bears against a free arm of one of said bell crank levers to pivot a contacting arm of one of said bell crank levers against the integrating plate to move the integrating plate out of contact with the cam follower when the cam follower is being moved from one cam to another.

6. The combination as set forth in claim 5 in which two cam followers are utilized and two separate operator influenced cam shifting means, and in which the projection means of a first of said operator influenced cam shifting means is carried by an axially shiftable rod and in which the'projection'means of the other of said operator influenced cam shifting means is carried by sleeve which is axially shiftable along the rod of said first operator influenced cam shifting means.

7. The combination as set forth in claim 6 in which each of the two cam followers is slidable and pivotally mounted on a separate post each of said posts being substantially j parallel to the cam shaft, and in which the two throw-out member bell crank levers are pivotally mounted on the same one of the posts;-

References Cited UNITED STATES PATENTS 3,003,442 10/1961 Yasui.

RICHARD J. SCANLAN, J 11., Primary Examiner 

